Answer:

insulates

Answer	Crossword Clue
INSULATES	Acts to prevent leakage
INSULATES	Employs glass wool
INSULATES	Winterizes, in a way

INSULATES	Cuts off
INSULATES	Does an electrician's job.

Crossword

a puzzle consisting of a grid of squares and blanks into which words crossing vertically and horizontally are written according to clues.